PIAA is releasing another headlight in about three weeks from Japan called the Xtreme White. It is rated a higher white and higher wattage than the current favorite Super Plasma Bulb. It appears that it will come in H4, H3, and even wedge bulbs (side markers).

 

now u gotta worry bout upgrading your wiring and hope it doesn't melt your housing.

 

For 10-15 additional watts on low setting I would not think you need to replace harness. In fact they are still lower in wattage than high lights in current PIAA form. It appears they made have just made a darker blue film to place on the Super White bulbs to try and match the HID craze at a fraction of the cost.